const mongoose = require('mongoose');

const questionSchema = new mongoose.Schema({
    type: {
        type: String,
        enum: ['single', 'multiple', 'text'],
        required: true
    },
    question: {
        type: String,
        required: true
    },
    options: [String],
    answer: mongoose.Schema.Types.Mixed, // 可以是索引、索引数组或字符串
    score: {
        type: Number,
        required: true
    }
});

const examSchema = new mongoose.Schema({
    title: {
        type: String,
        required: true
    },
    description: String,
    duration: { // 考试时长(分钟)
        type: Number,
        required: true
    },
    questions: [questionSchema],
    createdBy: {
        type: mongoose.Schema.Types.ObjectId,
        ref: 'User',
        required: true
    },
    createdAt: {
        type: Date,
        default: Date.now
    },
    isActive: {
        type: Boolean,
        default: true
    }
});

module.exports = mongoose.model('Exam', examSchema);